JPS62102001A - Fluidized bed boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluidized bed boiler that heats the boiler by combustion using a fluidized bed.

[Prior art]

A conventional fluidized bed boiler of this kind is, for example, the bubbling bed type shown in FIG. The fluidized air supplied to the air chamber 4 blows out to form a fluidized bed 5.

Fuel such as municipal waste is supplied into the combustion furnace 1 from the fuel supply device 6 and burned in the fluidized bed 5, and the combustion exhaust gas enters the freeboard section 7 and heats boiler water in the freeboard heat exchanger tube 9 of the boiler 8. The exhaust gas is then cooled and sent through the flue 10 to the exhaust gas treatment device.

In this type of fluidized bed boiler, in order to adjust the temperature of the fluidized bed 5, heat transfer tubes 11 are provided in the fluidized bed 5 to recover heat from the fluidized medium.

Further, as another conventional example, a circulation type example is shown in FIG. In this circulating type, the fluidized bed is not a fluidized bed that always has a free surface of fluidized medium.

The fluidization speed is increased to disperse and burn the fluidized medium and fuel throughout the furnace, the high-temperature fluidized medium is collected outside the furnace, and the amount of heat is obtained by a heat exchanger outside the furnace.

In FIG. 3, the fluidized medium leaves the freeboard section 7 with the exhaust gas and enters the cyclone 12, where it is separated and collected at the bottom of the cyclone 12. The exhaust gas from which the fluidizing medium has been separated is sent to the next facility via the flue 13.

The fluidized medium at the bottom of the cyclone 12 is led into a heat exchanger chamber 14 . A distribution plate 15 is provided at the bottom of the heat exchanger chamber 14, and the fluidized air supplied to the air chamber 17 from the fluidized air supply pipe 16 blows out to form a fluidized bed 18. A heat transfer tube 19 is disposed in a portion of this flow 111B, and the heat possessed by the fluid medium is recovered. The cooled fluidized medium is again supplied to the combustion furnace 1, and the temperature of the fluidized bed 5 is adjusted.

[Problem that the invention seeks to solve]

However, these conventional devices have the following problems.

For example, in the bubbling bed type shown in FIG. 2, the heat exchanger tubes 11 are disposed in the fluidized bed 5 with rapid movement, so that the heat exchanger tubes 11 are subject to considerable wear. In addition, it is difficult to adjust the amount of heat obtained from the fluidized bed 5, and furthermore, if non-combustible materials are included, the non-combustible materials will become entangled in the heat transfer tubes 11 and accumulate, resulting in poor heat transfer. could not be used.

In the circulation type shown in Figure 3, the power for fluidization becomes larger, the freeboard part becomes larger, and the equipment (cyclone) that collects the scattered high-temperature fluid medium becomes larger, resulting in an increase in the exhaust gas attraction pressure. There were problems such as.

The present invention solves the above-mentioned problems of the conventional ones, is small in size, consumes little power, prevents wear of heat transfer tubes that recover heat from the fluidized medium, makes it easy to adjust the temperature of the fluidized bed, and eliminates incombustible materials. The object is to provide a fluidized bed boiler that allows the use of mixed fuel.

[Means for solving problems]

As a means for solving the above-mentioned problems, the present invention provides a fluidized bed boiler in which a fluidized bed that always has a free surface of the fluidized medium is formed in the lower part of the combustion furnace, and heating is achieved by combustion in the fluidized bed. At the outside of the combustion furnace,
A heat exchanger chamber containing a heat exchanger is provided, and an upper part of the heat exchanger chamber and the furnace chamber of the combustion furnace are connected to a connection port provided on a side wall above the furnace bottom of the fluidized bed section of the combustion furnace. It is an object of the present invention to provide a fluidized bed boiler, characterized in that the fluidized medium is communicated with the heat exchanger chamber to flow into the heat exchanger chamber, and the fluidized medium extracted from the lower part of the heat exchanger chamber is returned to the fluidized bed section. It is something to do.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

The fluidized bed 5 in FIG. 1 is operated under conditions such that it always has a free surface 20 of fluidized medium.

A heat exchanger chamber 22 containing a heat exchanger 21 is provided outside the combustion furnace 1, and the upper part of the heat exchanger chamber 22 and the furnace chamber of the combustion furnace 1 are located above the bottom of the fluidized bed 5. It communicates through a connection port 24 provided in the side wall 23 of. The connection port 24 is provided at a position away from the fuel supply port 25.

In the heat exchanger chamber 22, a dispersion device 26 is provided in the lower part, and the fluidized medium is transferred to the heat transfer tubes of the heat exchanger 21 by the fluidized air supplied from the forced air blower [28 through the fluidized air supply pipe 27]. It is kept in a fluid state for optimum heat.

The fluidized medium in the heat exchanger chamber 22 is extracted by a feeder 29 at the bottom and transferred to a lifting device 3 such as a conveyor or pneumatic transport.
0 is again returned to the flow @5 parts in the combustion furnace 1.

31 is a temperature regulator that detects the temperature of the fluidized bed 5 and controls the temperature of the fluidized bed 5 by operating the feeder 29.

32 is a feeder for discharging incombustible materials accumulated on the distribution plate 2.

33 is an exhaust gas duct.

When the fluidized medium circulation device consisting of the feeder 29 and the pumping device 30 is activated by a signal from the temperature controller 31 or other instructions, the level of the fluidized medium in the heat exchanger chamber 22 is lowered, and the fluidized fluidized medium is Since the angle of repose of is small and the surface of the fluidized medium always tends to be flat, a part of the fluidized medium in the fluidized bed 5 in the combustion furnace 1 flows into the heat exchanger chamber 22 through the connection port 24, and the surface of the fluidized medium in the heat exchanger 21 It flows through contact with.

The heat of the fluidized medium flowing through the heat exchanger 21 is recovered as hot water or steam by the heat exchanger tubes of the heat exchanger 21.

Non-combustibles mixed with fuel and thrown into the combustion furnace l settle in the fluidized bed 5, reach the top of the dispersion plate 2, move downward, and are taken out by the feeder 32 for removing non-combustibles, so that heat exchange is performed. No incombustible material enters the chamber 22.

The above-described embodiment achieves the following effects by being configured as described above.

(1) Heat exchanger chamber 22 containing heat exchanger tubes of heat exchanger 21
By providing the heat exchanger tubes outside the combustion furnace 1, wear of the heat exchanger tubes is significantly reduced.

The fluidization velocity within the fluidized bed must be maintained at a constant value to maintain optimal combustion. Further, the amount of wear increases in proportion to the square to the third power of the fluidization speed of the fluid medium.

The dispersion device 26 provided at the bottom of the external heat exchanger chamber 22 in this embodiment provides appropriate fluidization to improve the heat transfer coefficient, which is far greater than the strength of fluidization in the fluidized bed combustion furnace 1. Therefore, the amount of wear on the heat exchanger tubes of the heat exchanger 21 is significantly reduced.

(2) The amount of heat recovered from the fluidized medium can be recovered by adjusting the amount of fluidized media passing through the heat exchanger 21 by changing the operating time or operating speed of the fluidized media circulating device consisting of the feeder 29 and the pumping device 30. The temperature within the flow M5 can be maintained at a temperature suitable for combustion, and stable combustion can be continued. Furthermore, even if the temperature of the fluidized medium in the heat exchanger chamber 22 drops to room temperature, the fluid cannot be extracted from the heat exchanger chamber 22.
2, the fluidic medium circulation power does not change.

(3) By communicating the upper part of the heat exchanger chamber 22 and the furnace chamber of the combustion furnace 1 through a connection port provided on the side wall above the furnace bottom of the fluidized bed 5 section of the combustion furnace 1, heat exchange is possible. Inflammables that would cause trouble to the heat transfer tubes of the vessel 21 are prevented from flowing into the heat transfer tubes, and the heat transfer tubes are not entangled with the incombustibles, thereby preventing poor heat transfer due to accumulation of noncombustibles. Therefore, even fuels mixed with nonflammable substances can be used.

〔Effect of the invention〕

The present invention is compact and consumes little power, significantly reduces wear on the heat exchanger tubes of the heat exchanger that recovers heat from the fluidized medium, makes it easy to adjust the temperature of the fluidized bed, and uses raw materials containing nonflammable materials. It is possible to provide a fluidized bed boiler that enables this, and has extremely great practical effects.

[Brief explanation of drawings]

FIG. 1 is a flow diagram of an embodiment of the present invention, and FIGS. 2 and 3 are flow diagrams of a conventional example. ■...Combustion furnace, 2...Dispersion plate, 3...Fluidized air supply pipe, 4...Air chamber, 5...Fluidized bed, 6...Fuel supply machine, 7... Freeboard section, 8...boiler,
9... Freeboard heat exchanger tube, IO... Flue, 11.
...heat exchanger tube, 12...cyclone, 13...flue,
14... Heat exchanger chamber, 15... Distribution plate, 16...
Fluidized air supply pipe, 17... Air chamber, 18... Fluidized bed, 19... Heat transfer tube, 20... Free surface, 21...
・Heat exchanger, 22... Heat exchanger room, 23... Side wall,
24... Connection port, 25... Fuel supply port, 26...
Dispersion device, 27... Fluidization air supply pipe, 28... Forced blower, 29... Feeder, 30... Lifting device,
31... Temperature controller, 32... Feeder, 33...
・Exhaust gas duct.

Claims (1)

[Claims] 1. In a fluidized bed boiler in which a fluidized bed having a free surface of the fluidized medium is always formed in the lower part of the combustion furnace and heated by combustion in the fluidized bed, outside the combustion furnace, A heat exchanger chamber containing a heat exchanger is provided, and an upper part of the heat exchanger chamber and the furnace chamber of the combustion furnace are connected through a connection port provided on a side wall above the furnace bottom of the fluidized bed section of the combustion furnace. A fluidized bed boiler, characterized in that the fluidized medium is communicated with the heat exchanger chamber to flow into the heat exchanger chamber, and the fluidized medium extracted from the lower part of the heat exchanger chamber is returned to the fluidized bed section.